1. Field of the Invention
The present invention relates generally to a redundant configurable VCSEL (vertical cavity surface emitting laser) laser array optical light source which is designed to provide for a selection of the best aligned and coupled laser to provide the nest laser signal from an array of surface emitting lasers. More particularly, the present invention pertains to a redundant configurable VCSEL laser array optical light source which provides for integrating optical communications capabilities into existing manufacturing processes, such as manufacturing processes for a substrate or submount such as a silicon or ceramic substrate, a multi-chip module, a package board, backplane or similar component.
2. Discussion of the Prior Art
The prior art has addressed the general concept of providing a fiber guide on an optoelectronic chip. In the early days of LED development, Burrus developed a relatively crude fiber guide for an LED in which a well is etched into an LED, and a butt-coupled fiber is inserted therein and then epoxied in place. A fiber guide fabricated to tighter tolerances than those offered by the Burrus approach is desirable so that a fiber may be aligned more precisely to an optoelectronic chip.
Accordingly, it is a primary object of the present invention to provide a redundant configurable VCSEL laser array optical light source which provides for integrating optical communications capabilities into manufacturing processes for a substrate or submount such as a silicon or ceramic substrate, a multi-chip module, a package board, backplane or similar component.
The present invention addresses the problem of providing optical connectors from one or more optical sources on a semiconductor laser chip mounted on a substrate or submount. In a typical application, the optical communications may be provided inside a computer and between a backplane and a circuit board or between two circuit boards. A typical optical source is a VCSEL (vertical cavity surface emitting laser) laser array chip comprising an array of VCSELs. The optical path can be provided by an optical fiber, typically glass or plastic, or by an optical waveguide fabricated from a material such as glass or another oxide or nitride or a polymer. The optical path could also be a free space optical path, i.e. consist of a lens or lenses and a transparent medium such as air. The optical detector can typically be a photodiode.
A key problem in the industry, which is addressed and solved by the present invention, is overcoming misalignments introduced in connector systems used to link the optical source(s) or detector(s) to the optical path. In the prior art, an optical fiber is often misaligned with a single laser optical source which is used and limited by the tolerances in the optical connector of whatever form or type. This misalignment has been a recognized major industry problem associated with the use of optics for high speed communications.
The present invention provides a new approach and structure to overcome alignment problems, and is designed to provide for a selection of the best aligned and coupled laser to provide the best laser signal from an array of surface emitting lasers.
The ability to physically fit more than one laser into the core size of a fiber was not heretofore possible, but is now possible as advances in semiconductors outpace reductions in fiber core diameter.
The present invention provides multiple, spatially proximate lasers and photodetectors as part of an optical transmitter or receiver module to simplify assembly of the module. One step in the assembly of the module requires alignment of a laser or photodetector to a transmission medium of the optical link, typically an optical fiber or waveguide. With multiple lasers or photodiodes in near proximity, those laser(s) or photodiodes(s) are selected which are strongly coupled to the transmission medium. Particularly in the case of multichannel modules, this approach greatly simplifies optical alignment, to improve yield and relax mechanical tolerances, leading to lower assembly costs and higher manufacturing yields.
One embodiment of the present invention uses a VCSEL laser array supported by a CMOS logic control chip, both packaged on a multichip module which provides an optical fiber connector/support structure, wherein the connections may be made with less demanding tolerances by virtue of the present invention.